What about mass?
I think this is going to remain implausible. The premise supposes an extra dimension exists that we don't yet know about, and that all the $3+1$ dimensional matter we see day-to-day is really just $4+1$ affixed to a common plane on one of those spatial dimensions.
Which is fine up until you realise that matter not on our common plane has mass too, and we should feel the gravity of that matter.
But we don't. And it'd be hard to imagine a world where we would feel this extra gravity and still have relate-able experiences.
But what if the universe was mostly empty in the extra dimension?
Well that would fit suitably, but it implies there's something special or different about that dimension. It's not a normal spatial dimension.
Let's forget about that for a moment though. Let's pretend we have a $4+1$ space, and for whatever reason, matter is all on one hyper-plane of that space.
Gravity feels exactly the same in this as it does in 'normal' space. In fact, mathematically, it's impossible to observe the difference.
By definition, there's no extra stuff in the extra dimension, so we can't mine it for valuables.
Transportation is basically wormholes, but gravity leaks through - in both directions! You could be tempted to hop off the conventional hyper-plane to travel in a straight line from $A$ to $B$, but there would be no ground to prevent gravity from sucking you down into the centre of the Earth.
Another question I have relates to light. If the fourth spatial dimension is behaviourally, the same as the other three, light should travel through it just fine. Anything that produces light in our dimensions should also produce light in that one too!
Quantum mechanics gets interesting here, as mass curves space, and light follows that curvature. Squint your eyes and look at this from a funny angle and you could justify this as an explanation for quantum tunnelling.
And here's where it goes to hell. Electrons have mass, and electrons are also very well known to exhibit quantum tunnelling. Following the idea of photons, electrons are temporarily venturing off our hyper-plane to tunnel around solid matter. Protons and neutrons do this too. Small atoms do it. Large atoms do it. Small molecules do it. There's an unspoken contest within the physics community to demonstrate larger and larger objects exhibit quantum mechanical effects.
There's literally no reason why mass shouldn't be everywhere in this extra dimension.
I think you want a dimension that doesn't follow the 'normal' physics rules.
You might prefer $3+2$ dimensions. But you might get weirder results from that.